1. Field of the Invention
The present invention relates to a coupling for drivingly coupling winding devices of adjacent architectural coverings. More in particular the invention relates to such force transmitting couplings that include a first coupling member, a second coupling member and engagement means between the first and second coupling members adapted to provide angular adjustment between the winding devices of the two adjacent architectural coverings.
2. Description of the Relevant Art
It has been proposed in WO 2006/102894 to obtain angular fine adjustment between blind rollers by providing a wrap spring coupling between the two blind rollers, which normally is in frictional engagement, but which can be disengaged for making fine adjustments. While this arrangement has provided for accurate adjustment in aligning the lower blind edges of adjacent roller blinds, it has also offered little resistance against peak torques that can occur during operation of the blinds, from disturbing the adjustments made. Such peak torques are due to inherent inertia in the blinds themselves as well as changes in operating direction and/or speed. It has thus been proposed, such as in DE 19546203, to resort to structural mating engagement between the adjustable drive coupling members to prevent the adjusted angular position from becoming disturbed by operating forces. However with larger blind units, such as often encountered in utility buildings, there have been cases where operating peak torques have completely ripped off the mating structural means that provided the positive engagement between the coupling members.